Mechanism of enzyme catalysis

Standard free energy of activation

Enzymes, like any other catalysts do not change reaction equilibrium. Enzymes change only the standard free energy barrier due in course of reaction. Reaction catalysed by enzyme in course of reaction path through several transitional states with standard free energy of activation of each state lover than the standard free energy of activation of non-catalysed reaction. The overall enzyme-catalysed reaction performed according following pathway:

E + S <-> ES <-> EP <-> E + P

This reaction pathway can be schematically show by following standard free energy profile of course of reaction. TSc1, TSc2, TSc3 - transitional states of enzyme-catalysed reaction.

Profile of standard free energy of activation in course of enzyme-catalysed reaction.

More detailed description of catalytic mechanism will be given for each enzyme.